The systematic synthesis of septacidin analogs will provide a structurally new class of potential antitumor agents. Septacidin is a nucleoside antibiotic with demonstrated antitumor and cytotoxic activity. As a nucleoside in which the sugar is attached to the 6-amino group of the adenine moiety, septacidin is structurally unique. The proposed analogs will be the first such nucleoside isomers to be synthesized intentionally and characterized. Known synthetic methods can be applied in these new syntheses. Enhanced activity was previously observed with a few analogs obtained from degradation studies on spetacidin.